Super Advantage

Oh man how I wish I had one of these! It looks like the ultimate stick. Tons of turbo buttons, slow button, and a few things I don't know what they do. It looks like there is a power and reset button on the controller that look like the ones on the Super NES. I suppose that is so you don't have to walk over to your console. Then there is a slider in the middle above the slow button which I don't know what it does. Give me some feedback on this beauty if you've had or tried it. You can get them for about $18 used or $60 new.